Why doesn't return work in java?

Question

Java

Return does not work in the say() (class Pet) method when I call from the super class, the same situation when I call the say() (class Fish) method from the main, here I tried to override the say () method from the Pet class.

one)

public class Pet {
    int age;
    float weight;
    float height;
    String color;

    public void sleep() {
        System.out.println("Спокойной ночи! До завтра");
    }

    public void eat() {
        System.out.println("Я очень голоден, давайте перекусим чипсами!");
    }

    public String say(String aWord){
        String petResponse = "Ну ладно " + aWord;
        return petResponse;
    }
}

2)

public class Fish extends Pet {


    int currentDepth = 0;

    public int dive(int howDeep) {
        currentDepth = currentDepth + howDeep;
        System.out.println("Ныряю на глубину " + howDeep + " футов");
        System.out.println("Я на глубине " + currentDepth + " футов ниже уровня моря");
        return currentDepth;
    }
    public String say(String something) {
        return "Рыбы не разговаривают";
    }
    }

3)

I call in the main:

public class PetMaster {
    public static void main(String[] args) {
        Pet myPet = new Pet();
        Fish myFish = new Fish();
        myPet.say("давай");
        myFish.say("давай");
    }
}